Metal salts of alkenyl succinic acids are known. For instance, U.S. Pat. No. 3,271,310 teaches that a "metal salt of hydrocarbon-substituted succinic acid having at least 50 aliphatic carbon atoms in the hydrocarbon substituent, the metal of the metal salt being selected from the class consisting of Group I metals, Group II metals, aluminum, lead, tin, cobalt and nickel" is useful as a dual purpose (detergent/rust inhibitor) additive.
Similarly, U.S. Pat. No. 4,552,677 discloses a similar material in which the preferred metal in the salt is copper and the hydrocarbon substituent contains from 8 to 35 carbon atoms.
U.S. Pat. No. 4,234,435 discloses that certain of the salts disclosed in U.S. Pat. No. 3,271,310 are useful as dispersant/detergents and viscosity index improvers. The salts contain an acylating agent derived from polyalkenes, such as polybutenes, and a dibasic, carboxylic reactant such as maleic or fumaric acid. The acylating agents are specifically characterized in that the polyalkenes from which they are derived include those in which the polybutene moiety has a M.sub.n of from about 1,300 to about 5,000, a M.sub.w /M.sub.n ratio of between about 1.5 and 4.0, and in which the ratio of the succinic acid moiety to the polybutene substituent is at least 1.3.
U.S. Pat. No. 3,714,042 relates to the treatment of basic metal sulfonate complexes, sulfonate-carboxylate complexes and carboxylate complexes with high molecular weight carboxylic acids to prepare additives useful in lubricating oils and gasolines. The patentee teaches the ineffectiveness of preformed metal salts of high molecular weight carboxylic acids for such treatments, and exemplifies the sediment formation resulting from use of the calcium salt of polyisobutenyl succinic anhydride at low concentrations in a mineral lubricating oil.